linux-kernel - [PATCH 3/4] sched/idle,stop: Remove .get_rr_interval from sched

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Date:   Wed,  3 Jun 2020 10:03:03 +0200
From:   Dietmar Eggemann <dietmar.eggemann@....com>
To:     Ingo Molnar <mingo@...hat.com>,
        Peter Zijlstra <peterz@...radead.org>
Cc:     Vincent Guittot <vincent.guittot@...aro.org>,
        Steven Rostedt <rostedt@...dmis.org>,
        Juri Lelli <juri.lelli@...hat.com>,
        linux-kernel@...r.kernel.org
Subject: [PATCH 3/4] sched/idle,stop: Remove .get_rr_interval from sched_class

The idle task and stop task sched_classes return 0 in this function.

The single call site in sched_rr_get_interval() calls
p->sched_class->get_rr_interval() only conditional in case it is
defined. Otherwise time_slice=0 will be used.

The deadline sched class does not define it. Commit a57beec5d427
("sched: Make sched_class::get_rr_interval() optional") introduced
the default time-slice=0 for sched classes which do not provide this
function.

So .get_rr_interval for idle and stop sched_class can be removed to
shrink the code a little.

Signed-off-by: Dietmar Eggemann <dietmar.eggemann@....com>
---
 kernel/sched/idle.c      | 7 -------
 kernel/sched/stop_task.c | 8 --------
 2 files changed, 15 deletions(-)

diff --git a/kernel/sched/idle.c b/kernel/sched/idle.c
index b743bf38f08f..70ea8565ae48 100644
--- a/kernel/sched/idle.c
+++ b/kernel/sched/idle.c
@@ -442,11 +442,6 @@ prio_changed_idle(struct rq *rq, struct task_struct *p, int oldprio)
 	BUG();
 }
 
-static unsigned int get_rr_interval_idle(struct rq *rq, struct task_struct *task)
-{
-	return 0;
-}
-
 static void update_curr_idle(struct rq *rq)
 {
 }
@@ -475,8 +470,6 @@ const struct sched_class idle_sched_class = {
 
 	.task_tick		= task_tick_idle,
 
-	.get_rr_interval	= get_rr_interval_idle,
-
 	.prio_changed		= prio_changed_idle,
 	.switched_to		= switched_to_idle,
 	.update_curr		= update_curr_idle,
diff --git a/kernel/sched/stop_task.c b/kernel/sched/stop_task.c
index 4c9e9975684f..3e50a6a8f1e5 100644
--- a/kernel/sched/stop_task.c
+++ b/kernel/sched/stop_task.c
@@ -102,12 +102,6 @@ prio_changed_stop(struct rq *rq, struct task_struct *p, int oldprio)
 	BUG(); /* how!?, what priority? */
 }
 
-static unsigned int
-get_rr_interval_stop(struct rq *rq, struct task_struct *task)
-{
-	return 0;
-}
-
 static void update_curr_stop(struct rq *rq)
 {
 }
@@ -136,8 +130,6 @@ const struct sched_class stop_sched_class = {
 
 	.task_tick		= task_tick_stop,
 
-	.get_rr_interval	= get_rr_interval_stop,
-
 	.prio_changed		= prio_changed_stop,
 	.switched_to		= switched_to_stop,
 	.update_curr		= update_curr_stop,
-- 
2.17.1